Play with the inventory

The board shows geometric opportunities; the reserve determines which you can execute. Before choosing a placement pair, count available copies of every required number. Two projects may fit spatially yet compete for the same last copy. Inventory is complete information: you do not need to guess which numbers the opponent owns.

Because each player has four copies of every value, a number’s reserve is four minus the tiles of that color and value on the board. If Blue has three 6s placed, one 6 remains. Red’s tiles do not enter that subtraction. Recalculate after removals rather than holding onto an outdated picture of the reserve.

A line 5–5–5–5 uses every copy of your 5s. You cannot simultaneously build a different matching line of 5s: any different line would require at least a fifth physical tile of that number. Sharing a cell does not solve the problem, because two distinct sets of four cells have a union larger than four.

By contrast, a matching line of 5s and one of 7s are automatically disjoint. No tile can carry both 5 and 7. If both are completed, they survive every removal. This pattern combines a substantial reserve requirement with a simple proof of independence. Check that both really are complete before relying on the guarantee.

A straight uses one copy of four different numbers and leaves more copies of each value for other projects. Ascending ranges of four are 1–4, 2–5, 3–6, 4–7 and 5–8. The numbers 4 and 5 each appear in four ranges; 1 and 8 appear in only one. The complete counts are 1, 2, 3, 4, 4, 3, 2 and 1.

This explains one source of flexibility for central values, but does not prove placing a 4 is always better than placing a 1. Orientation, empty cells and existing tiles can make an endpoint exactly the decisive number. Use the count to generate options and the particular position to choose among them.

When you remove a red 7, Red recovers a 7 for later turns. If those copies were exhausted, you have just enabled another placement of that value. This does not mean avoiding its removal when mandatory: preventing immediate defeat takes priority. When several defenses work, it can help compare their consequences.

Your own reserve also changes when the opponent removes a tile. A broken matching group leaves a copy available to repair it or support a different project. Do not assume the recovered tile must return to the same place. Ask whether using it elsewhere completes another structure or avoids concentrating all your lines around a shared defense again.

Before spending two tiles of one number, check which other projects need them. If you have three 3s on the board, only one remains available: a pair requiring two more 3s is impossible. You can change one project, seek a straight using other values or reconsider the cells, but cannot count the last copy twice.

Preserving flexibility can help when there is no immediate win, but saving a number is not a goal in itself. If spending your last copies completes two resilient lines, the game will be decided after the opposing removal. When you cannot guarantee that result, compare the continuations each remaining reserve permits and which tiles the opponent might return to you.

Removing a tile returns its value to the opposing reserve. If several removals defend equally well, compare what the opponent could build with the returned tile. Never sacrifice a necessary defense to save ammunition: avoid losing first, then choose among safe alternatives.

Staircases spread their cost across several values; four equal tiles use all four copies of one value. This makes 4 and 5 flexible seeds, 3 and 6 useful extensions, and 1 or 8 possible staircase finishers near an edge. These are guidelines: an equal-value line may be the best concrete move.

With only one reserve tile you can place only one. With none, you still remove a tile and check whether an opposing line survives; then your placements are skipped. Reserve limits your options, but it is not a countdown clock: removals recycle tiles.